Page 502 - 5G Basics - Core Network Aspects

1 Core network aspects

UE TAA-FE MLM-FE(P) HDC-FE NID-FE NIR-FE RACF
Successful
network attachment
Network selection key
transfer indication (Table 3)
Previous handover is completed
UE moves and determines that another handover is required...
Handover candidate indication (Table 6)
Available resource query (Table 14)
Available resource query response (Table 15)
Handover candidate response (Table 7)

If network makes handover decision... Access network information
query (Table 23)

Access network information
query response (Table 24)

Select and prepare
new link
Network handover decision request (Table 8)
Network handover decision response (Table 9)

If UE makes handover decision...
Access network information query (Table 12)

Access network information query response (Table 13)
Select new link
UE handover decision request (Table 10)

Prepare
new link
UE handover decision response (Table 11)
Y.2018(09)_F07

Figure 7 – Illustration of network discovery and decision procedure –
Network-triggered handover

7.3.2 Pre-authentication and pre-authorization
NOTE – The procedures of this clause require changes to [ITU-T Y.2014].
As the result of the network discovery and decision process, one target network is selected for the upcoming
handover. Before the handover, pre-authentication and pre-authorization in the new target network will be
performed while still connecting to the serving network. Figure 8 shows three cases.

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